The Trace

Before the Republic fell, before the Legions disappeared, before Core and the Vaults, history claims there was one world. This one forgotten world birthed a being or beings who changed the face of the galaxy. This unnamed and perhaps imaginary person discovered the Trace.

The Trace is difficult to describe, after all, it is an invisible phenomenon. The closest analogy would be a ball of gravity at the center of ten-thousand times ten-thousand infinitely long strings of anti-gravity. Each strand is stretched taut between the center and the edge of the Universe.

By riding the strings, modern pilots can traverse known space in gravity-driven ships. Two things are important, and affect all ships, from Corsair to Vault yachtsman. One: Shit rolls downhill; it is much easier and faster to travel towards the core than it is to travel away from it. (Down means coreward universally and Up means towards the Edge) Two: The strands move; just because you left a strand here two days ago does not mean that you will ever find one here again. There are patterns to the strands, but they defy mathematics, and it takes long years to learn them.

These two universals have, through no conscious action of their own, organized sentient life in known space into the Spheres. Near the core, where the strands are the closest together, it is virtually impossible to lose a strand. Even if the one you are looking for is missing, it's a short hop to one with a similar path. Far out, near the Edge, the strands are light years apart, and sometimes do not appear in the vicinity of a particular planet for decades. The republic delineated the Seven Spheres hundreds of years ago, and no one has found a better way to organize the strata of known space in the time since.